Is The Sugar In Fruit Bad For Your Bones? - Save Our Bones

Today’s article addresses a question frequently posed by Savers: does the sugar content of fruit outweigh the benefits of its bone-healthy nutrients and alkalizing effect? Sugar, if consumed in excess, leads to many health ailments, and it weakens bones. Most fruits contain high amounts of sugar, yet they are alkalizing Foundation Foods that offer bone-essential nutrients.

These sort of pros-vs-cons quandaries abound in health and nutrition – but there is a clear path forward. We can assess the impact of different fruits on blood sugar levels by looking at two measures: Glycemic Index (GI) and the more useful Glycemic Load (GL).

After a breakdown of what these two measures mean, we’ll look at the GI and GL values for a variety of fruits, and detail a plan of action to help you make the best choices for your body and your bones.

Why You Should Avoid Sugar

Refined white sugar– the kind found in processed foods and sweets– wreaks havoc on every system in your body: the brain, the digestive tract, the cardiovascular system, the immune system, and your bones. From your liver to your pancreas to your kidneys, too much sugar can lead to disease and dysfunction.

Sugar has a degenerative effect on your brain by promoting the formation of Advanced Glycation End products (AGEs). These sugar-bonded proteins weaken collagen, a major building block of the bone matrix, and build up in the brain, contributing to the beta-amyloid plaques and neurofibrillary tangles that contribute to Alzheimer’s disease.1

Sugar also cripples your ability to successfully break down and neutralize foreign matter like bacteria and pathogens, therefore weakening your immune system.2 It also competes with Vitamin C, utilizing the same pathways in and out of cells, effectively blocking this immune-supporting nutrient.

Most pressingly for Savers, sugar robs your bones of the minerals necessary for bone remodeling that keep bones resilient and young. Calcium, copper, and magnesium– all essential for the creation of new bone– are each impeded by sugar. 3,4,5

Considering how devastating sugar is to your body, sugary foods, especially processed foods, should be avoided. But what about fruits?

Fruits: Healthy Foods Or Sugary Temptation?

From cherries to watermelons, pineapples to pears, most fruits are classified as Foundation Foods in the Osteoporosis Reversal Program. That means they’re an essential part of maintaining a pH-balanced diet that provides your bones with the micronutrients they need to grow strong. Different fruits contain different beneficial compounds, but they’re bearers of antioxidants, flavonoids, potassium, vitamins, and minerals. Reams of research confirm that these phytonutrients, vitamins, and minerals increase bone density and improve overall health.6

Bear in mind that the sugar in fruits is composed of fructose and glucose, just like table sugar or sucrose, but the ratios differ slightly. For sucrose the ratio is 50/50, and for most fruits, it’s 40/55, but with some variations.

We also know that fruits are sweet. That makes them a welcome addition to the Saver’s diet, especially since the sugars in fruits are natural, which makes them far less of a problem than the refined sugars in processed foods. However, they still have an impact on our blood sugar levels. When we assess how sugary a fruit is, what we look at is this impact, which scientists measure in two related ways: Glycemic Index (GI) and Glycemic Load (GL).

Defining Glycemic Index

A food’s Glycemic Index is a number that describes how much that food will increase your blood sugar level. GI is based on a scale from 0 to 100, in which 100 is the blood sugar increase caused by consuming pure glucose. Food with a low GI (below 55) doesn’t have a significant impact on blood glucose levels, while food with a high GI (70 or above) will cause a sharp spike. Everything in the middle is considered an average score.

When you consume high-GI foods, they cause a drastic increase in blood glucose that quickly declines because of an insulin surge. In contrast, low-GI foods increase blood glucose more moderately, and the levels decrease much more gradually.

Glycemic Index is not always useful for determining the impact of the food on your plate. That’s because GI doesn’t consider typical portion sizes. It measures the blood sugar increase for a serving size that contains 50 grams of carbohydrates.

For some foods that might be far less than you would put on your plate, and for others, it might be more than you could eat in one sitting. You reach 50 grams of carbohydrates after just a few bites of a candy bar, but you’d have to eat five whole oranges to consume the quantity that their GI measures.

To address this problem, scientists at Harvard University devised a measurement that reflects typical serving sizes: Glycemic Load.

Defining Glycemic Load

The glycemic load is calculated directly from the glycemic index, but it also takes into consideration the amount of carbohydrates contained in a single serving. A certain food might have a high GI but a low GL if each serving doesn’t include many carbs.

Watermelon is a good example. It has a GI of 80, which is high, but the GI system bases that score on consuming 50 grams of watermelon-carbohydrates. A single serving of watermelon only contains 6 grams of available carbohydrate though, so unless you eat five servings at once, it doesn’t have a negative impact on your blood glucose levels.

The GL score is calculated by multiplying the GI by the grams of available carbohydrate per serving, then dividing by 100. If we follow the equation for watermelon, we multiply a GI of 80 by 6 (the grams of carbohydrate per serving) to get 480, then divide by 100 for a GL of 4.8.

GL scores of 10 or below are considered low. Scores of 11 to 19 are average, and anything above 19 is a high GL. Once you know the GL of the fruits in your diet, you can make informed decisions about the impact they have on your body, and moderate your consumption accordingly.7,8

A Handy Guide To The Glycemic Load Of Common Fruits

Use this table to find out the GL of these common fruits, pulled from studies of establishing the GL of a wide range of foods. The list is in descending order for glycemic load.

Fruit Glycemic Index Serving Size (grams) Glycemic Load (per serving)
Raisins* 64 60g 28
Dates (dried)* 42 60g 18
Figs 60 60g 16
Banana* 48 120g 11
Grapes (black)* 59 120g 11
Prunes (pitted)* 29 60g 10
Peach (canned)* 52 120g 9
Cherries* 22 120g 9
Mango 56 120g 8
Kiwi* 52 120g 7
Pineapple* 66 120g 6
Apple* 36 120g 5
Blueberries* 54 120g 5
Oranges* 45 120g 5
Peach* 42 120g 5
Pear (canned) 44 120g 5
Plum 24 120g 5
Watermelon* 72 120g 5
Cantaloupe 67 120g 4
Guava* 78 120g 4
Nectarines 30 120g 4
Pear* 38 120g 4
Apricot* 23 120g 3
Grapefruit* 25 120g 3
Lemon* 25 120g 3
Lime* 24 120g 1
Strawberries* 41 120g 1

*Indicates Foundation Foods

Remember that these figures are for fresh, raw fruits unless otherwise noted. Dried fruit and fruit juices are far more sugary than fresh fruit, and have a much higher Glycemic Load.

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As shown in the above table, many delicious alkalizing fruits have a low GL, so you can safely incorporate them into your pH-balanced diet. And remember that you can still eat fruits with the higher GL, but in moderation.

Till next time,

References:

1 Nobuyuki, Sasaki, et al. “Advanced Glycation End Products in Alzheimer’s Disease and Other Neurodegenerative Diseases.” The American Journal of Pathology. 1998 October; 153(4): 1149–1155. Web. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1853056/

2 Sanchez, Albert J.L., et al. “Role of sugars in human neutrophilic phagocytosis.” The American Society for Clinical Nutrition. 1973 Nov; 26(11):1180-4. Web. https://ajcn.nutrition.org/content/26/11/1180.abstract%29

3 Lawoyin, S., et al. “Bone mineral content in patients with calcium urolithiasis.” Metabolism 28:1250-1254.1979.

4 Swaminathan, R. “Magnesium Metabolism and its Disorders.” The Clinical Biochemist Reviews. 2003 May; 24(2): 47-66. Web. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1855626/

5 Wapnir, RA and Devas, G. “Copper deficiency: interaction with high-fructose and high-fat diets in rats.” The American Society for Clinical Nutrition, Inc. January 1995. Vol. 61 no. 1; 105-110. Web. https://ajcn.nutrition.org/content/61/1/105.abstract

6 Rao, L.G.; Kang, N., and Rao, A.V. “Polyphenol Antioxidants and Bone Health: A Review.” Phytochemicals – A Global Perspective of Their Role in Nutrition and Health. Dr. Venketeshwer Rao (Ed.): ISBN: 978-953-51-0296-0. InTech. PDF. https://cdn.intechopen.com/pdfs-wm/32957.pdf

7 Harvard University. Glycemic index and glycemic load for 100+ foods. Harvard Health Publishing. February, 2015. Web: https://www.health.harvard.edu/diseases-and-conditions/glycemic-index-and-glycemic-load-for-100-foods

8 Atkinson FS, Foster-Powell K, Brand-Miller JC. “International Tables of Glycemic Index and Glycemic Load Values: 2008.” Diab
Care 2008; 31(12) Web. https://care.diabetesjournals.org/content/suppl/2008/09/18/dc08-1239.DC1/TableA1_1.pdf

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Comments on this article are closed.

  1. Francesca

    Thank you so much for this article! A question: how is one serving of fruit measured and what is that quantity? Also, I have heard that 50 grams of sugar is the maximum for health. Do you also feel that way?

    • Vivian Goldschmidt, MA

      Per the FoodNetwork, here are some examples of 1 serving of fruit:

      Apple: ½ large (3.25″diameter), 1 small (2.5″ diameter)
      Banana: 1 large (8-9” long) or 1 cup sliced
      Cantaloupe: 1 cup of cubed melon or 2 medium wedges (about ¼ of a medium melon)
      Grapes: 1 cup whole or sliced or 32 seedless grapes
      Grapefruit: 1 medium (4″ diameter) or 1 cup sectioned
      Orange: 1 large (3-1/16″ diameter)
      Peach: 1 large (2-3/4″ diameter), 1 cup sliced or 1 cup canned and drained peaches
      Pear: 1 medium (2 ½ per pound), 1 cup sliced or 1 cup canned and drained pears
      Pineapple: 1 cup sliced, diced, or crushed, 1 cup cooked or 1 cup canned and drained
      Plum: 3 medium or 2 large, or 1 cup sliced or cooked
      Strawberries: 8 large, 1 cup whole, halved or sliced, fresh or frozen
      Watermelon: 1 cup cubed or 1 small wedge (1″ thick)

  2. Carl

    What source of sugar is best for cooking and for over all health?
    My wife and I love to read the great info you provide on your website and often send it to friends and family. Thank you.

    • Vivian Goldschmidt, MA

      Thanks for your kind words, Carl! We recommend using stevia.

  3. shula

    This is a valuable chart for fruit-consumption. Thank you.

    • Vivian Goldschmidt, MA

      My pleasure!

  4. Glory

    Great article! The explanation of GI and GL is really helpful along with the chart of fruit. Thank you!

    • Vivian Goldschmidt, MA

      You’re welcome!

  5. Femi Irewolede

    A highly illuminating article. Thank you for sharing the knowledge as always.
    T’will be nice though to include foods like Honey, Sweet Potatoes etc on that list to guide Savers.
    Cheers.

  6. Pat Dixon

    I am hypoglycemic and I avoid all sugar and fruit except for lemon and blueberry. Could this be responsible for my low t-score of 3.6?

    • Vivian Goldschmidt, MA

      There are so many factors that influence bone health, Pat, that it’s impossible to say for sure whether your lack of fruit consumption was the culprit behind your T-scores. But if you’d like to start including more fruits in your diet, perhaps this chart will help you choose fruits with a low GL. It also helps to combine fruits with a protein, such as unsweetened almond butter.

  7. Marlene

    Good morning Vivian,
    Excellent . Thank you very much for sharing a
    timely information.

    Have a wonderful day.
    Marlene

    • Vivian Goldschmidt, MA

      You’re welcome, Marlene!

  8. Mary Mackinnon

    Thank you for this very informative article on sugar. It has been a problem for me because I am quite addicted, but having the chart will help me to make the right choices. I’m going to print it and stick it on my fridge.

    • Vivian Goldschmidt, MA

      You’re welcome, Mary, and that’s a great idea about posting the list on your refrigerator. It might not hurt to make a small copy to take with you to the grocery store, too! 🙂

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